A. Technical Field
The present invention pertains generally to data processing, and relates more particularly to obtaining three-dimensional (3D) current from data obtained from an array of magnetic sensors.
B. Background of the Invention
Diagnostic tests are central to patient care. Healthcare professionals need the ability to evaluate patients in order to correctly diagnosis ailments. Diagnostics procedures can be invasive or non-invasive. Because invasive tests carry associated risks, non-invasive diagnostic procedures are often preferred. Non-invasive tests are particularly preferred when investigating critical organs, such as the heart and brain.
One form of non-invasive diagnostic tests is magnetic source imaging. Certain organs of the body, such as the heart and brain, generate currents. These currents arise in the synchronous activity of neurons of the organs, and the electric current produces magnetic fields that extend outside the body. Recording magnetic fields produced by the heart is known as magnetocardiography (MCG), and recording of magnetic fields produced by the brain is known as magnetoencephalography (MEG).
Using these magnetic fields as a diagnostic tool presents challenges. First, although these magnetic fields extend outside the body, they typically are very weak and require extremely sensitive measuring equipment. For example, an array of superconducting quantum interference device (SQUID) detectors can be placed near the organ of interest to detect magnetic fields.
Second, once the measurement data has been taken, the next obstacle is to make the data meaningful. Several prior attempts have made use of such measured data. MCG sensor data has been used to develop two-dimensional (2D) images. Other uses of the data involve displaying magnetic field mapping, which shows the distribution of the magnetic field obtained at specific measurement points and precise moments of time.
Attempts have been made to reconstruct the current distribution of the organ of interest; however, to achieve such a result an inverse problem must be solved. Namely, given the resultant magnetic field, one must attempt to ascertain what system of electrical current sources of the organ produced it. Solving this inverse problem is quite complex, and to reduce this complexity, many prior attempts have simplified the inverse problem in order to reach a result. However, simplifications tend to yield less accurate or in complete results. Accordingly, it is important that magnetic source imaging solutions model the organ as accurately as possible.